add eagerness property to speculation rules

.size-limit.json

@@ -1,22 +1,22 @@
 [
   {
     "path": "dist/quicklink.js",
-    "limit": "2.36 kB",
+    "limit": "2 kB",
     "gzip": true
   },
   {
     "path": "dist/quicklink.mjs",
-    "limit": "2.36 kB",
+    "limit": "2 kB",
     "gzip": true
   },
   {
     "path": "dist/quicklink.modern.mjs",
-    "limit": "1.91 kB",
+    "limit": "1.6 kB",
     "gzip": true
   },
   {
     "path": "dist/quicklink.umd.js",
-    "limit": "2.43 kB",
+    "limit": "2 kB",
     "gzip": true
   }
 ]

package.json

@@ -1,6 +1,6 @@
 {
   "name": "quicklink",
-  "version": "2.4.0",
+  "version": "2.3.0",
   "description": "Faster subsequent page-loads by prefetching in-viewport links during idle time",
   "repository": {
     "type": "git",

src/chunks.mjs

@@ -15,7 +15,7 @@
  **/
 
 import throttle from 'throttles';
-import {viaFetch, supported} from './prefetch.mjs';
+import {priority, supported} from './prefetch.mjs';
 import requestIdleCallback from './request-idle-callback.mjs';
 
 // Cache of URLs we've prefetched
@@ -145,7 +145,7 @@ export function prefetch(url, isPriority) {
         // ~> so that we don't repeat broken links
         toPrefetch.add(str);
 
-        return (isPriority ? viaFetch : supported)(
+        return (isPriority ? priority : supported)(
             new URL(str, location.href).toString(),
         );
       }),

src/index.mjs

@@ -15,7 +15,7 @@
  **/
 
 import throttle from 'throttles';
-import {prefetchOnHover, supported, viaFetch} from './prefetch.mjs';
+import {prefetchOnHover, supported} from './prefetch.mjs';
 import requestIdleCallback from './request-idle-callback.mjs';
 import {addSpeculationRules, hasSpecRulesSupport} from './prerender.mjs';
 
@@ -72,8 +72,6 @@ function checkConnection(conn) {
  * @param {Object} options - Configuration options for quicklink
  * @param {Object|Array} [options.el] - DOM element(s) to prefetch in-viewport links of
  * @param {Boolean} [options.priority] - Attempt higher priority fetch (low or high)
- * @param {Boolean} [options.checkAccessControlAllowOrigin] - Check Access-Control-Allow-Origin response header
- * @param {Boolean} [options.checkAccessControlAllowCredentials] - Check the Access-Control-Allow-Credentials response header
  * @param {Boolean} [options.onlyOnMouseover] - Enable the prefetch only on mouseover event
  * @param {Array} [options.origins] - Allowed origins to prefetch (empty allows all)
  * @param {Array|RegExp|Function} [options.ignores] - Custom filter(s) that run after origin checks
@@ -151,8 +149,7 @@ export function listen(options = {}) {
           // Do not prefetch if will match/exceed limit and user has not switched to shouldOnlyPrerender mode
           if (toPrefetch.size < limit && !shouldOnlyPrerender) {
             toAdd(() => {
-              prefetch(hrefFn ? hrefFn(entry) : entry.href, options.priority,
-                  options.checkAccessControlAllowOrigin, options.checkAccessControlAllowCredentials, options.onlyOnMouseover)
+              prefetch(hrefFn ? hrefFn(entry) : entry.href, options.priority, options.onlyOnMouseover)
                   .then(isDone)
                   .catch(error => {
                     isDone();
@@ -207,13 +204,10 @@ export function listen(options = {}) {
 * Prefetch a given URL with an optional preferred fetch priority
 * @param {String} url - the URL to fetch
 * @param {Boolean} isPriority - if is "high" priority
-* @param {Boolean} checkAccessControlAllowOrigin - true to set crossorigin="anonymous" for DOM prefetch
-*                                                    and mode:'cors' for API fetch
-* @param {Boolean} checkAccessControlAllowCredentials - true to set credentials:'include' for API fetch
 * @param {Boolean} onlyOnMouseover - true to enable prefetch only on mouseover event
 * @return {Object} a Promise
 */
-export function prefetch(url, isPriority, checkAccessControlAllowOrigin, checkAccessControlAllowCredentials, onlyOnMouseover) {
+export function prefetch(url, isPriority, onlyOnMouseover) {
   const chkConn = checkConnection(navigator.connection);
   if (chkConn instanceof Error) {
     return Promise.reject(new Error(`Cannot prefetch, ${chkConn.message}`));
@@ -232,8 +226,7 @@ export function prefetch(url, isPriority, checkAccessControlAllowOrigin, checkAc
         // ~> so that we don't repeat broken links
         toPrefetch.add(str);
 
-        return prefetchOnHover((isPriority ? viaFetch : supported), new URL(str, location.href).toString(), onlyOnMouseover,
-            checkAccessControlAllowOrigin, checkAccessControlAllowCredentials, isPriority);
+        return prefetchOnHover((isPriority ? viaFetch : supported), new URL(str, location.href).toString(), onlyOnMouseover);
       }),
   );
 }

src/prefetch.mjs

@@ -31,17 +31,13 @@ function hasPrefetch(link) {
 /**
  * Fetches a given URL using `<link rel=prefetch>`
  * @param {string} url - the URL to fetch
- * @param {Boolean} hasCrossorigin - true to set crossorigin="anonymous"
  * @return {Object} a Promise
  */
-function viaDOM(url, hasCrossorigin) {
+function viaDOM(url) {
   return new Promise((resolve, reject, link) => {
     link = document.createElement('link');
     link.rel = 'prefetch';
     link.href = url;
-    if (hasCrossorigin) {
-      link.setAttribute('crossorigin', 'anonymous');
-    }
 
     link.onload = resolve;
     link.onerror = reject;
@@ -53,16 +49,13 @@ function viaDOM(url, hasCrossorigin) {
 /**
  * Fetches a given URL using XMLHttpRequest
  * @param {string} url - the URL to fetch
- * @param {Boolean} hasCredentials - true to set withCredentials:true
  * @return {Object} a Promise
  */
-function viaXHR(url, hasCredentials) {
+function viaXHR(url) {
   return new Promise((resolve, reject, request) => {
     request = new XMLHttpRequest();
 
-    request.open('GET', url, request.withCredentials = hasCredentials);
-
-    request.setRequestHeader('Accept', '*/*');
+    request.open('GET', url, request.withCredentials = true);
 
     request.onload = () => {
       if (request.status === 200) {
@@ -81,26 +74,21 @@ function viaXHR(url, hasCredentials) {
  * Fetches a given URL using the Fetch API. Falls back
  * to XMLHttpRequest if the API is not supported.
  * @param {string} url - the URL to fetch
- * @param {Boolean} hasModeCors - true to set mode:'cors'
- * @param {Boolean} hasCredentials - true to set credentials:'include'
- * @param {Boolean} isPriority - true to set priority:'high'
  * @return {Object} a Promise
  */
-export function viaFetch(url, hasModeCors, hasCredentials, isPriority) {
+export function priority(url) {
   // TODO: Investigate using preload for high-priority
   // fetches. May have to sniff file-extension to provide
   // valid 'as' values. In the future, we may be able to
   // use Priority Hints here.
   //
   // As of 2018, fetch() is high-priority in Chrome
   // and medium-priority in Safari.
-  const options = {headers: {accept: '*/*'}};
-  if (!hasModeCors) options.mode = 'no-cors';
-  if (hasCredentials) options.credentials = 'include';
-  isPriority ? options.priority = 'high' : options.priority = 'low';
-  return window.fetch ? fetch(url, options) : viaXHR(url, hasCredentials);
+  return window.fetch ? fetch(url, { credentials: 'include' }) : viaXHR(url);
 }
 
+export const supported = hasPrefetch() ? viaDOM : viaXHR;
+
 /**
  * Calls the prefetch function immediately
  * or only on the mouseover event.
@@ -137,5 +125,3 @@ export function prefetchOnHover(callback, url, onlyOnMouseover, ...args) {
     el.addEventListener('mouseleave', mouseleaveListener);
   }
 }
-
-export const supported = hasPrefetch() ? viaDOM : viaFetch;